12/23/2014 9:50 AM PST

The Lead singer of Say Anything hurled on stage Monday night ... soaking a security guard in vomit.

Lead singer Max Bemis was towards the end of the set at the House of Blues in West Hollywood when he projectile vomited without warning. It's unclear why ... but there was alcohol on stage so it ain't that hard to read between the lines.

Bemis didn't miss a beat, and continued singing "I Want to Know Your Plans." As for the security guard ... well it definitely ruined his night.